Dual additive composition for polishing memory hard disks exhibiting edge roll off

Abstract

The invention provides a chemical-mechanical polishing composition comprising (a) an abrasive comprising colloidal silica, (b) a compound of formula (I), (c) a compound of formula (II), (d) hydrogen peroxide, and (e) water, wherein the polishing composition has a pH of about 1 to about 5. The invention also provides a method of chemically-mechanically polishing a substrate, especially a nickel-phosphorous substrate, by contacting the substrate with the inventive chemical-mechanical polishing composition.

The invention claimed is: 
     
       1. A chemical-mechanical polishing composition comprising:
 (a) an abrasive comprising colloidal silica, 
 (b) about 0.001 wt. % to about 1 wt. % of a compound of formula (I): 
 
       
         
           
           
               
               
           
         
         
           wherein R is 
           CH 2 ═CHCONHC(CH 3 ) 2 CH 2 —, 
           wherein X is independently O or a covalent bond, 
         
         or an alkali metal salt thereof, 
         (c) a compound of formula (II): 
       
       
         
           
           
               
               
           
         
         wherein R 9  is H or a hydroxyalkyl, and 
         wherein m is an integer of from 2 to about 6, 
         (d) hydrogen peroxide, and 
         (e) water,
 wherein the polishing composition has a pH of about 1 to about 5. 
 
       
     
     
       2. The polishing composition of  claim 1 , wherein the colloidal silica has an average particle size of about 10 nm to about 200 nm. 
     
     
       3. The polishing composition of  claim 1 , wherein the abrasive further comprises fused silica. 
     
     
       4. The polishing composition of  claim 3 , wherein the fused silica has an average particle size of about 100 nm to about 800 nm. 
     
     
       5. The polishing composition of  claim 1 , wherein the compound of formula (I) is 2 acrylamido-2-methyl-1-propanesulfonic acid. 
     
     
       6. The polishing composition of  claim 1 , wherein the compound of formula (II) is selected from ethylenediamine, 1,3-diaminopropane, and combinations thereof. 
     
     
       7. The polishing composition of  claim 1 , wherein the polishing composition comprises about 0.001 wt. % to about 1 wt. % of the compound of formula (II). 
     
     
       8. The polishing composition of  claim 1 , wherein the polishing composition comprises about 0.1 wt. % to about 10 wt. % of a combination of colloidal silica and fused silica. 
     
     
       9. A method of chemically mechanically polishing a substrate comprising:
 (i) providing a substrate, 
 (ii) providing a polishing pad, 
 (iii) providing a chemical-mechanical polishing composition comprising: 
 
       (a) an abrasive comprising colloidal silica, 
       (b) about 0.001 wt. % to about 1 wt. % of a compound of formula (I): 
       
         
           
           
               
               
           
         
         wherein R is 
         CH 2 ═CHCONHC(CH 3 ) 2 CH 2 —, 
         wherein X is independently O or a covalent bond, 
       
       or an alkali metal salt thereof, 
       (c) a compound of formula (II): 
       
         
           
           
               
               
           
         
       
       wherein R 9  is H or a hydroxyalkyl, and 
       wherein m is an integer of from 2 to about 6, 
       (d) hydrogen peroxide, and 
       (e) water, 
       wherein the polishing composition has a pH of about 1 to about 5,
 (iv) contacting the substrate with the polishing pad and the chemical-mechanical polishing composition, and 
 (v) moving the polishing pad and the chemical mechanical polishing composition relative to the substrate to abrade at least a portion of a surface of the substrate to thereby polish the substrate. 
 
     
     
       10. The method of  claim 9 , wherein the colloidal silica has an average particle size of about 10 nm to about 200 nm. 
     
     
       11. The method of  claim 9 , wherein the abrasive further comprises fused silica. 
     
     
       12. The method of  claim 11 , wherein the fused silica has an average particle size of about 100 nm to about 800 nm. 
     
     
       13. The method of  claim 9 , wherein the compound of formula (1) is 2 acrylamido-2-methyl-1-propanesulfonic acid. 
     
     
       14. The method of  claim 9 , wherein the compound of formula (II) is selected from ethylenediamine, 1,3-diaminopropane, and combinations thereof. 
     
     
       15. The method of  claim 9 , wherein the polishing composition comprises about 100 ppm to about 500 ppm of the compound of formula (I). 
     
     
       16. The method of  claim 9 , wherein the polishing composition comprises about 100 ppm to about 2000 ppm of the compound of formula (II). 
     
     
       17. The method of  claim 9 , wherein the polishing composition comprises about 0.1 wt. % to about 10 wt % of a combination of colloidal silica and fused silica. 
     
     
       18. The method of  claim 9 , wherein the substrate is a nickel-phosphorous-coated aluminum memory disk, wherein the substrate comprises nickel-phosphorous on a surface of the substrate, and wherein at least a portion of the nickel-phosphorous on a surface of the substrate is abraded to polish the substrate.